.\"     Title: \fBmysqlcheck\fR
.\"    Author: 
.\" Generator: DocBook XSL Stylesheets v1.70.1 <http://docbook.sf.net/>
.\"      Date: 03/31/2009
.\"    Manual: MySQL Database System
.\"    Source: MySQL 5.1
.\"
.TH "\fBMYSQLCHECK\fR" "1" "03/31/2009" "MySQL 5.1" "MySQL Database System"
.\" disable hyphenation
.nh
.\" disable justification (adjust text to left margin only)
.ad l
.SH "NAME"
mysqlcheck \- a table maintenance and repair program
.SH "SYNOPSIS"
.HP 46
\fBmysqlcheck [\fR\fB\fIoptions\fR\fR\fB] [\fR\fB\fIdb_name\fR\fR\fB [\fR\fB\fItbl_name\fR\fR\fB ...]]\fR
.SH "DESCRIPTION"
.PP
The
\fBmysqlcheck\fR
client checks, repairs, optimizes, and analyzes tables.
.PP
\fBmysqlcheck\fR
is similar in function to
\fBmyisamchk\fR, but works differently. The main operational difference is that
\fBmysqlcheck\fR
must be used when the
\fBmysqld\fR
server is running, whereas
\fBmyisamchk\fR
should be used when it is not. The benefit of using
\fBmysqlcheck\fR
is that you do not have to stop the server to check or repair your tables.
.PP
\fBmysqlcheck\fR
uses the SQL statements
CHECK TABLE,
REPAIR TABLE,
ANALYZE TABLE, and
OPTIMIZE TABLE
in a convenient way for the user. It determines which statements to use for the operation you want to perform, and then sends the statements to the server to be executed. For details about which storage engines each statement works with, see the descriptions for those statements in
Chapter\ 12, SQL Statement Syntax.
.PP
The
MyISAM
storage engine supports all four statements, so
\fBmysqlcheck\fR
can be used to perform all four operations on
MyISAM
tables. Other storage engines do not necessarily support all operations. In such cases, an error message is displayed. For example, if
test.t
is a
MEMORY
table, an attempt to check it produces this result:
.sp
.RS 3n
.nf
shell> \fBmysqlcheck test t\fR
test.t
note     : The storage engine for the table doesn't support check
.fi
.RE
.PP
The use of
\fBmysqlcheck\fR
with partitioned tables is not supported before MySQL 5.1.27.
.sp
.it 1 an-trap
.nr an-no-space-flag 1
.nr an-break-flag 1
.br
\fBCaution\fR
.PP
It is best to make a backup of a table before performing a table repair operation; under some circumstances the operation might cause data loss. Possible causes include but are not limited to file system errors.
.PP
There are three general ways to invoke
\fBmysqlcheck\fR:
.sp
.RS 3n
.nf
shell> \fBmysqlcheck [\fR\fB\fIoptions\fR\fR\fB] \fR\fB\fIdb_name\fR\fR\fB [\fR\fB\fItables\fR\fR\fB]\fR
shell> \fBmysqlcheck [\fR\fB\fIoptions\fR\fR\fB] \-\-databases \fR\fB\fIdb_name1\fR\fR\fB [\fR\fB\fIdb_name2\fR\fR\fB \fR\fB\fIdb_name3\fR\fR\fB...]\fR
shell> \fBmysqlcheck [\fR\fB\fIoptions\fR\fR\fB] \-\-all\-databases\fR
.fi
.RE
.PP
If you do not name any tables following
\fIdb_name\fR
or if you use the
\fB\-\-databases\fR
or
\fB\-\-all\-databases\fR
option, entire databases are checked.
.PP
\fBmysqlcheck\fR
has a special feature compared to other client programs. The default behavior of checking tables (\fB\-\-check\fR) can be changed by renaming the binary. If you want to have a tool that repairs tables by default, you should just make a copy of
\fBmysqlcheck\fR
named
\fBmysqlrepair\fR, or make a symbolic link to
\fBmysqlcheck\fR
named
\fBmysqlrepair\fR. If you invoke
\fBmysqlrepair\fR, it repairs tables.
.PP
The following names can be used to change
\fBmysqlcheck\fR
default behavior.
.TS
allbox tab(:);
l l
l l
l l.
T{
\fBmysqlrepair\fR
T}:T{
The default option is \fB\-\-repair\fR
T}
T{
\fBmysqlanalyze\fR
T}:T{
The default option is \fB\-\-analyze\fR
T}
T{
\fBmysqloptimize\fR
T}:T{
The default option is \fB\-\-optimize\fR
T}
.TE
.sp
.PP
\fBmysqlcheck\fR
supports the following options:
.TP 3n
\(bu
\fB\-\-help\fR,
\fB\-?\fR
.sp
Display a help message and exit.
.TP 3n
\(bu
\fB\-\-all\-databases\fR,
\fB\-A\fR
.sp
Check all tables in all databases. This is the same as using the
\fB\-\-databases\fR
option and naming all the databases on the command line.
.TP 3n
\(bu
\fB\-\-all\-in\-1\fR,
\fB\-1\fR
.sp
Instead of issuing a statement for each table, execute a single statement for each database that names all the tables from that database to be processed.
.TP 3n
\(bu
\fB\-\-analyze\fR,
\fB\-a\fR
.sp
Analyze the tables.
.TP 3n
\(bu
\fB\-\-auto\-repair\fR
.sp
If a checked table is corrupted, automatically fix it. Any necessary repairs are done after all tables have been checked.
.TP 3n
\(bu
\fB\-\-character\-sets\-dir=\fR\fB\fIpath\fR\fR
.sp
The directory where character sets are installed. See
Section\ 9.2, \(lqThe Character Set Used for Data and Sorting\(rq.
.TP 3n
\(bu
\fB\-\-check\fR,
\fB\-c\fR
.sp
Check the tables for errors. This is the default operation.
.TP 3n
\(bu
\fB\-\-check\-only\-changed\fR,
\fB\-C\fR
.sp
Check only tables that have changed since the last check or that have not been closed properly.
.TP 3n
\(bu
\fB\-\-check\-upgrade\fR,
\fB\-g\fR
.sp
Invoke
CHECK TABLE
with the
FOR UPGRADE
option to check tables for incompatibilities with the current version of the server. This option automatically enables the
\fB\-\-fix\-db\-names\fR
and
\fB\-\-fix\-table\-names\fR
options.
\fB\-\-check\-upgrade\fR
was added in MySQL 5.1.7.
.TP 3n
\(bu
\fB\-\-compress\fR
.sp
Compress all information sent between the client and the server if both support compression.
.TP 3n
\(bu
\fB\-\-databases\fR,
\fB\-B\fR
.sp
Process all tables in the named databases. Normally,
\fBmysqlcheck\fR
treats the first name argument on the command line as a database name and following names as table names. With this option, it treats all name arguments as database names.
.TP 3n
\(bu
\fB\-\-debug[=\fR\fB\fIdebug_options\fR\fR\fB]\fR,
\fB\-# [\fR\fB\fIdebug_options\fR\fR\fB]\fR
.sp
Write a debugging log. A typical
\fIdebug_options\fR
string is often
\'d:t:o,\fIfile_name\fR'.
.TP 3n
\(bu
\fB\-\-debug\-check\fR
.sp
Print some debugging information when the program exits. This option was added in MySQL 5.1.21.
.TP 3n
\(bu
\fB\-\-debug\-info\fR
.sp
Print debugging information and memory and CPU usage statistics when the program exits. This option was added in MySQL 5.1.14.
.TP 3n
\(bu
\fB\-\-default\-character\-set=\fR\fB\fIcharset_name\fR\fR
.sp
Use
\fIcharset_name\fR
as the default character set. See
Section\ 9.2, \(lqThe Character Set Used for Data and Sorting\(rq.
.TP 3n
\(bu
\fB\-\-extended\fR,
\fB\-e\fR
.sp
If you are using this option to check tables, it ensures that they are 100% consistent but takes a long time.
.sp
If you are using this option to repair tables, it runs an extended repair that may not only take a long time to execute, but may produce a lot of garbage rows also!
.TP 3n
\(bu
\fB\-\-fast\fR,
\fB\-F\fR
.sp
Check only tables that have not been closed properly.
.TP 3n
\(bu
\fB\-\-fix\-db\-names\fR
.sp
Convert database names to 5.1 format. Only database names that contain special characters are affected. This option was added in MySQL 5.1.7.
.TP 3n
\(bu
\fB\-\-fix\-table\-names\fR
.sp
Convert table names to 5.1 format. Only table names that contain special characters are affected. This option was added in MySQL 5.1.7. As of MySQL 5.1.23, this option also applies to views.
.TP 3n
\(bu
\fB\-\-force\fR,
\fB\-f\fR
.sp
Continue even if an SQL error occurs.
.TP 3n
\(bu
\fB\-\-host=\fR\fB\fIhost_name\fR\fR,
\fB\-h \fR\fB\fIhost_name\fR\fR
.sp
Connect to the MySQL server on the given host.
.TP 3n
\(bu
\fB\-\-medium\-check\fR,
\fB\-m\fR
.sp
Do a check that is faster than an
\fB\-\-extended\fR
operation. This finds only 99.99% of all errors, which should be good enough in most cases.
.TP 3n
\(bu
\fB\-\-optimize\fR,
\fB\-o\fR
.sp
Optimize the tables.
.TP 3n
\(bu
\fB\-\-password[=\fR\fB\fIpassword\fR\fR\fB]\fR,
\fB\-p[\fR\fB\fIpassword\fR\fR\fB]\fR
.sp
The password to use when connecting to the server. If you use the short option form (\fB\-p\fR), you
\fIcannot\fR
have a space between the option and the password. If you omit the
\fIpassword\fR
value following the
\fB\-\-password\fR
or
\fB\-p\fR
option on the command line, you are prompted for one.
.sp
Specifying a password on the command line should be considered insecure. See
Section\ 5.5.6.2, \(lqEnd\-User Guidelines for Password Security\(rq.
.TP 3n
\(bu
\fB\-\-pipe\fR,
\fB\-W\fR
.sp
On Windows, connect to the server via a named pipe. This option applies only for connections to a local server, and only if the server supports named\-pipe connections.
.TP 3n
\(bu
\fB\-\-port=\fR\fB\fIport_num\fR\fR,
\fB\-P \fR\fB\fIport_num\fR\fR
.sp
The TCP/IP port number to use for the connection.
.TP 3n
\(bu
\fB\-\-protocol={TCP|SOCKET|PIPE|MEMORY}\fR
.sp
The connection protocol to use for connecting to the server. It is useful when the other connection parameters normally would cause a protocol to be used other than the one you want. For details on the allowable values, see
Section\ 4.2.2, \(lqConnecting to the MySQL Server\(rq.
.TP 3n
\(bu
\fB\-\-quick\fR,
\fB\-q\fR
.sp
If you are using this option to check tables, it prevents the check from scanning the rows to check for incorrect links. This is the fastest check method.
.sp
If you are using this option to repair tables, it tries to repair only the index tree. This is the fastest repair method.
.TP 3n
\(bu
\fB\-\-repair\fR,
\fB\-r\fR
.sp
Perform a repair that can fix almost anything except unique keys that are not unique.
.TP 3n
\(bu
\fB\-\-silent\fR,
\fB\-s\fR
.sp
Silent mode. Print only error messages.
.TP 3n
\(bu
\fB\-\-socket=\fR\fB\fIpath\fR\fR,
\fB\-S \fR\fB\fIpath\fR\fR
.sp
For connections to
localhost, the Unix socket file to use, or, on Windows, the name of the named pipe to use.
.TP 3n
\(bu
\fB\-\-ssl*\fR
.sp
Options that begin with
\fB\-\-ssl\fR
specify whether to connect to the server via SSL and indicate where to find SSL keys and certificates. See
Section\ 5.5.7.3, \(lqSSL Command Options\(rq.
.TP 3n
\(bu
\fB\-\-tables\fR
.sp
Overrides the
\fB\-\-databases\fR
or
\fB\-B\fR
option. All name arguments following the option are regarded as table names.
.TP 3n
\(bu
\fB\-\-use\-frm\fR
.sp
For repair operations on
MyISAM
tables, get the table structure from the
\fI.frm\fR
file so that the table can be repaired even if the
\fI.MYI\fR
header is corrupted.
.TP 3n
\(bu
\fB\-\-user=\fR\fB\fIuser_name\fR\fR,
\fB\-u \fR\fB\fIuser_name\fR\fR
.sp
The MySQL user name to use when connecting to the server.
.TP 3n
\(bu
\fB\-\-verbose\fR,
\fB\-v\fR
.sp
Verbose mode. Print information about the various stages of program operation.
.TP 3n
\(bu
\fB\-\-version\fR,
\fB\-V\fR
.sp
Display version information and exit.
.SH "COPYRIGHT"
.PP
Copyright 2007\-2008 MySQL AB, 2009 Sun Microsystems, Inc.
.PP
This documentation is free software; you can redistribute it and/or modify it only under the terms of the GNU General Public License as published by the Free Software Foundation; version 2 of the License.
.PP
This documentation is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
.PP
You should have received a copy of the GNU General Public License along with the program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110\-1301 USA or see http://www.gnu.org/licenses/.
.SH "SEE ALSO"
For more information, please refer to the MySQL Reference Manual,
which may already be installed locally and which is also available
online at http://dev.mysql.com/doc/.
.SH AUTHOR
MySQL AB (http://www.mysql.com/).
